Some people are born with a gene that helps them sleep better at night.

Scientists say this specific gene, required for normal sleep, makes you sleep fitfully or peacefully - depending on whether or not the gene is intact, according to Daily Mail.

Experts say this is the first insight into how our DNA affects our sleep-wake cycle.

Lead investigator Dr Jason Gerstner, an assistant research professor at Washington State University, said that as a doctoral student at the University of Wisconsin, he looked at genes that change expression over the sleep-wake cycle.

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He found that a gene called FABP7 changed over the day throughout the brain of mice.

The current study, conducted at WSU, looked at three different animals - mice, humans, and fruit flies - to explore how the gene affects sleep.

The team found that mice with the FABP7 gene intact tended to sleep better than those with an inactive version.

This suggested the gene is required for normal sleep in mammals.

Next, the researchers looked at data from nearly 300 Japanese men who underwent a seven-day sleep study that included an analysis of their DNA.

The researchers found that 29 of them had a variant of the gene responsible for the production of FABP7 - and, in turn, tended to have irregular sleeping patterns.

While they would get the same amount of sleep as the other participants, they would wake up intermittently throughout the night.

Finally, the researchers made transgenic fruit flies, which share 61 percent of disease-causing genes with humans.

They inserted both mutated and normal human FABP7 genes into star-shaped glial cells called astrocytes.

Glial cells were long thought to just support neurons, the processors of information in the brain.

But recent studies have shown that, like neurons, glial cells release chemical neurotransmitters and control behavior.

Researchers monitored the flies' sleep using a commercial monitor that automatically records activity changes via an infrared beam.

If the beam is unbroken for five or more minutes, the machine concludes the fly is asleep.

They found that flies with the mutated FABP7 gene broke the beam more frequently during normal sleep time.

Just like the mice and humans without a properly functioning FABP7 gene, mutant FABP7 flies slept more fitfully.

"This suggests that there's some underlying mechanism in astrocytes throughout all these species that regulates consolidated sleep," said Dr Gerstner.

"It's the first time we've really gained insight into a particular cell's and molecular pathway's role in complex behavior across such diverse species."

FABP7 proteins are also involved in what is called "lipid signaling", which move fats to a cell nucleus to activate genes controlling growth and metabolism.

Dr Gerstner and his colleagues plan to study how these functions might intersect with current theories about why sleep matters.

Some of these theories include: sleep being important for neuronal activity, energy use and storage, and memory and learning.